1. Field
Methods and apparatuses consistent with exemplary embodiments of the inventive concept relate to detecting camera tampering, and more particularly, detecting camera tampering, if a foreground ratio exceeds a reference value, a pixel value difference in an image lasts more than a predetermined time, or a global motion value exceeds a reference value.
2. Description of the Related Art
An image surveillance system obtains images from cameras installed at many places where surveillance is necessary, and transmits the images to a monitor or stores the images in a storage to monitor them in real-time and to review them afterwards.
Recently, as demands for image surveillance systems have generally increased in society as a whole, in order to solve a problem of manpower shortage for managing an increased number of image surveillance systems, intelligent image analyzing techniques in which detecting motion in an image, tracing an object in the image, or face recognition function has been developed.
An image analyzing technique includes a function of detecting a moving object from an image or a function of analyzing a behavior of the moving body. The image analyzing technique increases an efficiency of an image surveillance system since the image analyzing technique may replace or assist manpower required for managing a security system that detects trespassers and thefts or monitors a moving object.
A camera tampering detection system, as one of image analyzing techniques, is used for detecting an installed surveillance camera if the camera is artificially manipulated, damaged, or a view of the camera is blocked by objects such as blowing leaves.
The camera tampering detection system notifies a user of unexpected problems on a facility where the camera tampering detection is installed for crime prevention such as changes of an installation location, an angle of view of a camera, view blocking of the camera or a power outage of the camera.
Also, in a general image surveillance system, images are obtained from cameras installed on several places. Image signals obtained from the cameras are simultaneously managed by a user, for convenience of management, by being connected to a digital video recorder (DVR) or network video recorder (NVR).